Negative charge carrier resins with RH sensitivity

Abstract

The instant disclosure describes methacrylate coated carrier resins with hydrophobic substituents for charge control and improved RH sensitivity.

We claim: 
     
       1. A toner carrier composition comprising:
 a polymer coating resin consisting of a methacrylate monomer having a hydrophobic substituent and a secondary aminoacrylate monomer, wherein the highest occupied molecular orbital (HOMO) of the methacrylate-containing polymer has greater than about 25% of the electron density of those molecular orbitals located on the hydrophobic substituent and less than about 75% of the electron density of those molecular orbitals on the carbonyl group of the methacrylate moiety, and wherein said methacrylate monomer having a hydrophobic substituent is present from about 98% to 100% by weight of the polymer and said secondary aminoacrylate monomer is present (a) from about 0.5 to about 1%; or (b) from about 1 to about 1.5; or (c) from about 1.5 to about 2% by weight of the polymer, 
 further wherein the methacrylate monomer has the formula as set forth in formula (I): 
 
       
         
           
           
               
               
           
         
         wherein Ar comprises at least one aromatic group, and 
         the secondary amino acrylate monomer is selected from the group consisting of dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and diethylaminopropyl methacrylate; and 
         a carrier core particle, wherein the polymer coating resin adheres to a surface of the carrier core particle. 
       
     
     
       2. The Carrier composition of  claim 1 , wherein the monomer exhibits increased delocalization of Fukui (−) function electron densities from the carbonyl group to the hydrophobic substituent as compared to methyl-containing, hexyl-containing or cyclohexyl-containing methacrylate polymers. 
     
     
       3. The carrier composition of  claim 1 , wherein Ar is a benzyl group, a naphthyl group or a phenyl group. 
     
     
       4. The Carrier composition of  claim 1 , wherein the methacrylate monomer has a carbon oxygen (C/O) ratio of 4.75 or more. 
     
     
       5. The carrier composition of  claim 1 , wherein the secondary amino acrylate monomer is present at about 1% by weight of the polymer. 
     
     
       6. The carrier composition of  claim 1 , wherein said methacrylate monomer has an improved charging RH ratio as compared to that of methylmethacrylate (MMA). 
     
     
       7. A developer comprising:
 a carrier composition; 
 a toner; 
 and a toner surface additive; 
 wherein the carrier composition comprises a polymer coating resin consisting of a methacrylate monomer having a hydrophobic substituent and a secondary aminoacrylate monomer, wherein the highest occupied molecular orbital (HOMO) of the methacrylate-containing polymer has greater than about 25% of the electron density of those molecular orbitals located on the hydrophobic substituent and less than about 75% of the electron density of those molecular orbitals on the carbonyl group of the methacrylate moiety, and wherein said methacrylate monomer having a hydrophobic substituent is present from about 98% to 100% by weight of the polymer and said secondary aminoacrylate monomer is present (a) from about 0.5 to about 1%; or (b) from about 1 to about 1.5; or (c) from about 1.5 to about 2% by weight of the polymer, 
 further wherein the methacrylate monomer has the formula as set forth in formula (I): 
 
       
         
           
           
               
               
           
         
         wherein Ar comprises at least one aromatic group, and 
         the secondary amino acrylate monomer is selected from the group consisting of dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and diethylaminopropyl methacrylate; and 
         a carrier core particle, wherein the polymer coating resin adheres to a surface of the carrier core particle. 
       
     
     
       8. The developer of  claim 7 , wherein said at least one methacrylate monomer comprises a carbon:oxygen (C/O) ratio of 4.75 or greater. 
     
     
       9. The developer of  claim 7 , wherein said toner surface additive comprises a silica, a titania, an alumina or mixtures thereof. 
     
     
       10. The developer of  claim 9 , wherein said silica comprises at least one silica. 
     
     
       11. The developer of  claim 7 , wherein an energy gap for forward charge transfer of electrons for said at least one methacrylate monomer and a toner surface additive is at less than about 5.1 eV. 
     
     
       12. The developer of  claim 7 , wherein said toner comprises an emulsion aggregation toner. 
     
     
       13. The developer of  claim 7 , wherein Ar comprises a benzyl group or a phenyl group. 
     
     
       14. The developer of  claim 7 , wherein the secondary amino acrylate monomer is present at about 1% by weight of the polymer. 
     
     
       15. The developer of  claim 7 , wherein said at least one methacrylate monomer comprises an improved charging RH ratio as compared to that of methylmethacrylate (MMA).